1. Technical Field
The inventive concept generally relates to a semiconductor integrated circuit device, and more particularly, to a semiconductor integrated circuit device having a bulk bias control function, and a method of driving the same.
2. Related Art
In recent years, as semiconductor devices are increasingly scaled down, the density of transistors has increased rapidly, and voltage use has increasingly been lowered to reduce power consumption. To obtain the improved transition speed with a low voltage level, the threshold voltage is increasingly reduced, and thus sub-threshold leakage is emerging as a new problem.
To reduce the leakage current in the semiconductor integrated circuit devices, for example, semiconductor memory devices, a voltage having an absolute value larger than that of the source voltage is needed. This larger voltage is needed for providing the bulk of the transistors in a power-down mode.
Currently, in a PMOS transistor in which an external voltage VDD is applied as a source voltage, a boosting voltage VPP_EXT having a higher level than the external voltage may be applied as a bulk bias. In an NMOS transistor in which a ground voltage VSS is applied as a source voltage, a negative voltage VNN may be applied as a bulk bias.
However, with regards to a power-up period, the external voltage VDD, the boosting voltage may be abnormally input. Thus, an abnormal bulk voltage may be applied in a ramp-up period. This may cause bulk voltage reversal, and a large amount of leakage current may be generated.